More than 400,000 births in the US each year are to adolescent mothers and approximately 26-36% of these mothers experience postpartum depression (PPD), a condition associated with significant social and health morbidity. PPD puts adolescent mothers and their children at risk during an already challenging time in their lives and this hardship may be a major determinant of poor outcomes for these young mothers and their children. Depression in adolescent mothers may influence whether they engage in health-promoting behaviors both for themselves and their infants. Research to date has not focused on preventing PPD in adolescent mothers even though the potential for a positive public health impact is tremendous in this vulnerable population. The Project REACH application addresses the research objective outlined in PA 09-174: Women's Mental Health in Pregnancy and the Postpartum Period targeting intervention research to develop systematic knowledge about psychosocial depression treatments for perinatal mood disorders and to develop new behavioral interventions for these conditions, in particular interventions that can be adapted to general medical or group settings. Further, this application specifically targets a population of women particularly vulnerable to PPD because of their young age, low-income and diverse ethnic/racial backgrounds. The long-term objective of Project REACH (Relax, Encourage, Appreciate, Communicate, Help) is to improve health outcomes for adolescent mothers and their children by preventing PPD. To accomplish this goal, a feasible and acceptable evidence-based program to prevent PPD in adolescent mothers will be evaluated for efficacy in a prenatal setting serving a diverse population of pregnant women. The Specific Aim of Project REACH is to conduct a randomized controlled trial to evaluate whether the intervention (Project REACH) compared with a didactic attention-control program reduces the risk of PPD in adolescent mothers. Project REACH is based on Interpersonal Psychotherapy and targets those factors that may play a significant role in the development of PPD in adolescent mothers (i.e., poor social support, role transitions and life stressors). The highly structured intervention is delivered as five sessions during pregnancy with one postpartum booster session. Participants are evaluated for depression at 6-weeks, 3-month, 6-months and 12-months postpartum. In addition to PPD outcomes, Project REACH proposes to assess the impact of the intervention on maternal-child bonding and health promoting behaviors. The collaborative interdisciplinary research team is uniquely qualified to lead this application as they have successfully developed and pilot tested the innovative behavioral prevention program to prevent PPD in adolescent mothers. Through careful evaluation and refinement, Project REACH has been tailored for collaboration with an integrated prenatal care program; and, if found to be efficacious, REACH has the potential for broad dissemination and acceptability in prenatal practice.